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<div id="version" align=right><b>petsc-3.14.5 2021-03-03</b></div>
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<A NAME="SNESLINESEARCHCP"><H1>SNESLINESEARCHCP</H1></A>
Critical point line search. This line search assumes that there exists some artificial G(x) for which the <A HREF="../SNES/SNESFunction.html#SNESFunction">SNESFunction</A> F(x) = grad G(x). Therefore, this line search seeks to find roots of dot(F, Y) via a secant method.
<H3><FONT COLOR="#CC3333">Options Database Keys</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>-snes_linesearch_minlambda <minlambda> </B></TD><TD>- the minimum acceptable lambda
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>-snes_linesearch_maxstep <length> </B></TD><TD>- the algorithm insures that a step length is never longer than this value
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>-snes_linesearch_damping <damping> </B></TD><TD>- initial trial step length is scaled by this factor, default is 1.0
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>-snes_linesearch_max_it <max_it> </B></TD><TD>- the maximum number of secant steps performed.
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Notes</FONT></H3>
This method does NOT use the objective function if it is provided with <A HREF="../SNES/SNESSetObjective.html#SNESSetObjective">SNESSetObjective</A>().
<P>
This method is the preferred line search for <A HREF="../SNES/SNESQN.html#SNESQN">SNESQN</A> and <A HREF="../SNES/SNESNCG.html#SNESNCG">SNESNCG</A>.
<P>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../SNES/SNESLineSearchCreate.html#SNESLineSearchCreate">SNESLineSearchCreate</A>(), <A HREF="../SNES/SNESLineSearchSetType.html#SNESLineSearchSetType">SNESLineSearchSetType</A>()
<BR><P><B></B><H3><FONT COLOR="#CC3333">Level</FONT></H3>advanced<BR>
<H3><FONT COLOR="#CC3333">Location</FONT></H3>
</B><A HREF="../../../src/snes/linesearch/impls/cp/linesearchcp.c.html#SNESLINESEARCHCP">src/snes/linesearch/impls/cp/linesearchcp.c</A>
<BR><A HREF="./index.html">Index of all SNES routines</A>
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